The Sonic Cruiser. It was propose to require some rather substantial improvements in technology to achieve its stated goals of cruising at about Mach 0.95, compared to Mach 0.8 for most commercial airliners, over a range of between 6,000 nm and 10,000 nm (11,120 km to 18,530 km). What airline would want to fly that fast.

The BWB is related to the flying wing, but is a somewhat more sophisticated concept that resulted from a study to determine the optimum low-drag shape to contain a given volume of passenger space. The resulting fuselage resembles a flattened sphere that tapers down and blends into the outboard wings, hence the name Blended-Wing-Body. The thick center-section could hold some 500 to 800 passengers. Additional studies have focused on smaller variants in the 250- to 300-passenger range, and a study indicated that a cruise speed of Mach 0.9 over a range of 7,500 to 8,900 nm (13,875 to 16,465 km)?

Why were those aircrafts (and possibly more we don't know about) dropped?

I would think that they were dropped because no airline wanted to pay for it to be built. Boeing was not about to risk the company on an airliner that had no firm interest in a time where most airlines couldn't afford it if they wanted to. Now ANY airline would want a faster aircraft if it was economical, but it takes a lot of money to develop and test an entirely new aircraft.

The Concorde, of which only 14 were sold, was completely subsidized by France and the UK. The only airlines that got them were the national flag carriers Air France and British Airways. It was a great airplane, has yet to be equaled, but it was as much an achievement of engineering as it was a political achievement.

America landed on the Moon, The Soviets had a Space station and UK and France shared the Concorde.

In America the SST program was cancelled when it became apparent that the airlines could not operate it profitably. Boeing was well along with its SST and had to lay off thousands of engineers when it was cancelled. The 747 was supposed to be a passenger jet that would be easily converted to a freighter when the SST was available. Well, the 747 definitely outlived that era.

In the Soviet Union they finished their SST and it was a fine engineering effort but only a few ever served Aeroflot none were built for export and overall it never reached its potential. (You should read up on the Le Bourget crash of the TU-144 and the Mirage III near miss that caused it).

It's all about the money, but also about the return HORIZON. If investors had been willing to invest money with returns forecasted for 20 years hence, this sort of project would be easier. But of course the risk would still be great.

"There are no stupid questions, but there are a lot of inquisitive idiots."

The main reason why the Sonic Cruiser was dropped was due to the fact the plane didn't offer any serious time-saving advantages even on long-distance flights--and the development costs would have been extremely high indeed.

But all is not lost--from what I read recently in Popular Science Boeing has used its engineering studies on the Sonic Cruiser and applied the very latest in aerodynamic research on eliminating the pressure wave buildup during supersonic flight that causes the loud sonic boom. This could result in a Mach 1.5-1.7 SST seating 200 passengers that could fly as far as 7,000 nautical miles with NO audiable sonic boom on the ground, which means you could fly from the US West Coast to central Europe at supersonic speeds and nobody on the ground will complain.

The main reason is that airlines were not interested in investing money on a project which did not grant them a sure return. And if Boeing did not received a good feed-back from airlines, clearly the project dropped...
It's a market's law, it all depends on demand: you can build up an aircraft you believe is the perfect one but if no airline is interested in, why wasting money?

As for the BWB concept...do you really want to get a middle seat on that plane? There was talk of having a "concourse" on the exterior for pax to have a sense of space, but other than that, a passenger would have little in terms of natural light and it could get quite disorienting IMO. If passengers won't like it, neither will airlines, and neither will Boeing.

Let's not forget that the Sonic Cruiser was proposed before the economy went sour and the 9/11 attacks slammed the air travel industry. During the Roaring Nineties, the airlines were raking in money hand over fist, and they weren't too concerned about a slightly higher fuel burn if they could squeeze more money out of high-margin passengers by offering a faster cruise speed. By 2002, the picture had changed completely. Boeing reacted to the market and came up with a new design, which is a much better idea than stubbornly continuing with an aircraft the airlines don't want.

As far as I know, the BWB was never a serious offering. McDonnell Douglas did some BWB studies during its final years which were further developed by Boeing after the merger, but I don't think they've ever gone further than the concept stage. I don't expect to see a BWB for a long time, as Airbus has the very "stretchable" A380 and Boeing doesn't see any market for a second super-jumbo.

The other on-again off-again project at Boeing is the 747NG, which first saw life as the 747-500/600X in the mid-90s and again in 2000 as the less radical 747X/Stretch program, then as the 747-400XQLR derivative in 2002. Boeing never got a single order, so the aircraft were never built. A "747 Advanced" with some 7E7 technology incorporated seems to be the latest idea floating out of Everett.

Boeing's critics like to bash it for "losing focus" in the past few years, but I don't see anything wrong with presenting various designs to the market and seeing if there are any takers. Airbus does the same thing (e.g. A340-8000, A330-500, A330 'Lite') but just does it a little more discretely. True, Boeing has hit a rough patch with the 747, but they have too much invested in the aircraft to let it die without a fight. I think we'll continue to see Boeing pitching 747 derivatives until one sticks or production of the -400 is completed and the line closes.

You are kidding right? Every airline wants to fly as fast as possible. This gives passengers minimum time in the air, and that's what people want these days. Hardly any passengers wants to spend 8+ hours in the air, and having faster aircraft will shorten the time, perhaps dramatically on some routes, this will provide an extra marketing point for the airlines, and thus more ticket sales.

Just look at the Concorde, if it wasn't so expensive to run, and wasn't aimed at Business travel alone, it'd be a huge success, purely and simply because people want to get from A to B in the minimum amount of time possible.

The point is not what the manufacturers are thinking about, it´s only what they´re presenting as an official proposal. That´s where Boeing made a few mistakes, apparently; But having more or less exotic concepts in the drawer / on the harddisk is absolutely normal for every manufacturer.

SQ never owned a Concorde, just that BA operated BAH-SIN sectors operated with SQ flight numbers and 50% of the cabin crew being SIA.
Only OAD had SIA livery on one side only.
That US reg on one of the pics is a temporary reg used on all the fleet in 1979/80 to allow a IAD-DFW sector to be flown (overland at Mach 0.95) by Braniff crews.
Neither airline operated the aircraft in the sense that they fully crewed it, had it in only their livery, maintained it.

In a lot of games, including plane building, three strikes and you're out.

B was fortunate in one way, they had not advanced any further (spent more money) on the Sonic Cruiser program than they had when everyone pulled the plug. It would have been a huge white elephant if it had gone into production before things hit the fan.

One lesson learned from the Sonic Cruiser is estimating the potential risk of ending up with a white elephant if there are more economic "challenges" for the airline industry. I think that the 7E7 is fairly safe, but have some concerns about the 380 if the industry faces multiple problems like 9/11. I hope to fly both the 7E7 and 380 before I retire and wish both well, but the white elephant risk does concern me.